OHI Science | Citation policy
From Halpern et al. 2012 supplemental info:
The ‘Lasting Special Places’ sub-goal focuses instead on those geographic locations that hold particular value for aesthetic, spiritual, cultural, recreational or existence reasons57. This sub-goal is particularly hard to quantify. Ideally one would survey every community around the world to determine the top list of special places, and then assess how those locations are faring relative to a desired state (e.g., protected or well managed). The reality is that such lists do not exist. Instead, we assume areas that are protected represent these special places (i.e. the effort to protect them suggests they are important places).
Clearly this is an imperfect assumption but in many cases it will be true. Using lists of protected areas as the catalogue of special places then creates the problem of determining a reference condition. We do not know how many special places have yet to be protected, and so we end up having all identified special places also being protected. To solve this problem we make two important assumptions. First, we assume that all countries have roughly the same percentage of their coastal waters and coastline that qualify as lasting special places. In other words, they all have the same reference target (as a percentage of the total area). Second, we assume that the target reference level is 30% of area protected.
The model for this goal considers the inland coastal zone (up to 1 km inland) independently from, and equally weighted with, the offshore coastal zone (up to 3 nm offshore). The status for this goal is calculated as:
\[X_{LSP} = \frac{\left(\frac{Area_{P}}{Area_{P_{ref}}} + \frac{Area_{MPA}}{Area_{MPA_{ref}}}\right)}{2}\]
where:
New World Database on Protected Areas spatial data from UNEP-WCMC became available in May 2016. In addition, an error in the previous assessments (specifically the .csv used to determine total areas for the 3 nm offshore and 1 km inland regions) caused total region areas to be underestimated, artificially inflating scores in past assessments, in some cases quite significantly. This error has been fixed in the v2016 assessment, but in so doing, many of the reported scores are noticeably lower than before.
Reference: IUCN and UNEP-WCMC (2018), The World Database on Protected Areas (WDPA) [On-line], June 2018. Cambridge, UK: UNEP-WCMC. Available at: www.protectedplanet.net.
Downloaded: July 2, 2018
Description: Shapefile of World Database on Protected Areas
Time range: 1819 - 2018; some protected areas do not have an associated “status year” and are reported as year 0.
Format: Shapefile
File location: Mazu:git-annex/globalprep/_raw_data/wdpa_mpa/d2018/WDPA_June2018-shapefile/
The WDPA-MPA dataset comes as a shapefile or geodatabase in WGS84 coordinate reference system.
Once the polygons have been prepped, we rasterize the results to 500 m resolution.
This process is all done in the script: 1_prep_wdpa_rast.Rmd. After that is complete, move on to computing zonal statistics.
Comparing the global WDPA raster to the 3 nautical miles offshore and 1 km inland rasters, we can tally the protected area within each region and compare to the total area within each region. Note each cell is 500 m x 500 m, so area is .25 km2, but since we are simply calculating a ratio, this cancels out.
Once the WDPA raster is cross-tabulated against the OHI region rasters (both 3 nm offshore and 1 km inland) we have the number of protected cells, identified by year of protection, within each region. NA values are unprotected cells.
## year rgn_id n_cells
## Min. : 0 Min. : 1.0 Min. : 0
## 1st Qu.:1902 1st Qu.: 59.0 1st Qu.: 0
## Median :1941 Median :117.5 Median : 0
## Mean :1928 Mean :118.8 Mean : 5148
## 3rd Qu.:1980 3rd Qu.:178.0 3rd Qu.: 0
## Max. :2018 Max. :272.0 Max. :19687739
## NA's :223 NA's :156 NA's :1## year rgn_id n_cells
## Min. : 0 Min. : 1.0 Min. : 0
## 1st Qu.:1902 1st Qu.: 59.0 1st Qu.: 0
## Median :1941 Median :117.0 Median : 0
## Mean :1928 Mean :118.1 Mean : 4807
## 3rd Qu.:1980 3rd Qu.:177.0 3rd Qu.: 0
## Max. :2018 Max. :250.0 Max. :19875249
## NA's :222 NA's :156 NA's :1## year rgn_id n_cells
## Min. : 0 Min. : 1.00 Min. : 0
## 1st Qu.:1902 1st Qu.: 62.75 1st Qu.: 0
## Median :1941 Median :124.50 Median : 0
## Mean :1928 Mean :127.64 Mean : 67794
## 3rd Qu.:1980 3rd Qu.:188.25 3rd Qu.: 0
## Max. :2018 Max. :277.00 Max. :998232136
## NA's :237 NA's :156Grouping by rgn_id, the total number of cells per region is determined by summing cell counts across ALL years, including cells with year == NA (unprotected cells). We can then determine the protected area for each year by looking at the cumulative sum of cells up to any given year.
Since the cells are 500 m on a side, we can easily calculate area by multiplying cell count * 0.25 km2 per cell.
Finally we can calculate the status of a region for any given year by finding the ratio of protected:total and normalizing by the goal’s target of 30% protected area.
From the protected area files, write out the individual layers ready for the Toolbox[TM].
Some goals require calculation of resilience nearshore (3nm) or entire EEZ.
Plot scores for 2018 vs 2017 assessment years
Check outliers in Status plot
| rgn ID | rgn name | status diff | explanation |
|---|---|---|---|
| 153 | Cook Islands | 0 -> 100 | Partial update, including the addition of the 1.97 million km2 Marae Moana Marine Park marine protected area. The Marine Park was designated in July 2017 and encompasses the entire Cook Islands Exclusive Economic Zone. Marae Moana is now the largest protected area in the world. Protected area for both coastline and coastal marine area increased significantly for 2017 data due to this change. |
| 190 | Qatar | 0 -> 71 | |
| 249 | Sint Eustatius | 0 -> 54 | |
| 146 | Pitcairn | 0 -> 50 | |
| 154 | Niue | 0 -> 36 | |
| 173 | Uruaguay | 30 -> 97 | |
| 227 | Jersey | 30 -> 70 |